This invention relates to a technique for valve incision and a novel valvulotome for practicing this technique. More particularly, this invention relates to a new and improved technique for incising venous valves using a small amount of current in conjunction with a hooked, retrocutting knife. This invention is particularly well suited for removing valves of the autograft or allograft vein for bypass of arterial obliterative disease.
In 1949 Kunlin described the first bypasses of femoral arterial obliterative disease with autogenous saphenous vein grafts. These were used in the reversed position to permit flow through the venous valves with central orientation. Because of the major discrepancies in size between the proximal and distal saphenous vein found in some patients, May et al in 1959 developed a technique for use of the vein in the nonreversed position with an olive-tipped inside stripper which bluntly disrupted the valves and some inner venous lining as well (see May AG, DeWeese JA, Rob CG: Arterialized in situ saphenous vein Arch Surg 1965;91:743-750). Hall first reported this in situ technique in 1961, but used multilevel transverse venotomies and excision of the leaflets (see Hall KV: The great saphenous vein used in situ as an arterial shunt after extirpation of the vein valves: A preliminary report. Surgery 1962;51:492-495). This was less traumatic but was slow and tedious and conducive to scarring and stricture in the smaller veins. Connolly, Harris et al performed the "in situ" operation in 1962 adapting the olive tipped inside stripper suggested by May for the intraluminal destruction of the leaflets (see Connolly JE, Harris EJ and Mills W: Autogenous in situ saphenous vein bypass of femoral-popliteal obliterative disease. Surgery 1964;55:144-153). Criticisms of the operation included the dangers of residual arteriovenous fistulas, trauma to the endothelium from the rough disruption of the valves and stenoses at the valve sites from residual uncut cusps or trauma. Samuels et al reported a new valvulotome, since then copied by many even to the present time. This was introduced upward from the distal end of the vein, destroying valve competency as it was withdrawn blindly (see Samuels PB, Plested WG, Haberfelde, GC, et al: in situ saphenous vein arterial bypass. Am Surg 1968;34 122-130). In 1973 Skagseth and Hall devised a similar instrument with a retrocutting edge substituting it for the multiple venotomy technique they had first introduced (see Skagseth E, Hall KV: in situ vein bypass: Experiences with new vein valve strippers. Scand J Thorac Cardiovasc Surg 1973;7:53-58). Even the present modifications of these retrograde valvulotomes, with blind and traumatic disruptions of the valves, fail to accomodate to anomalies in the venous anatomy or abrupt changes in the vein sizes.
The procedure fell into disrepute in the 1970's after late results showed graft failure primarily from endothelial trauma and inadequate management of the valve excision. In 1976 Mills introduced a hooked, retrocutting knife for coronary bypass grafts which emphasized atraumatic division of the cusp (see Mills NL and Ochsner JL: Valvotomy of valves in saphenous vein graft before coronary artery bypass. J Thorac Cardiovasc Surg 1976;71:878-879). It was inserted distally and on withdrawal, engaged the individual cusp which was slightly distended and identified with gentle retrograde perfusion from the proximal vein. In 1979, Leather, Karmody et al reappraised the in situ procedure with the concept of gentle division of the cusps and introduced microvascular scissors proximal to the valves (see Leather RP, Powers SR, and Karmody AM: A reappraisal of the in situ saphenous vein arterial bypass: Its use in limb salvage. Surgery 1979:453-461). This technique was difficult to apply to the distal vein where the branches were too small to accept the scissors. In 1981 Leather reported a miniaturized Mills knife introduced from below the valves through the vein end or a convenient distal branch (see Leather RP, Shah DM, et al: Further experience with the saphenous vein used in situ for 15 arterial bypass. Am J Surg 1981;142:506).
With new, more gentle manipulation of grafts, the results of the in situ grafts improved. In 1981, the inventor herein and others began using the in situ in the leg and the nonreversed (or orthograde) free grafts for coronary bypass and a variety of procedures throughout the vascular tree (see Donovan TJ and Lowe R: Biologic fate of valves in reversed and nonreversed arterial vein grafts. Am J Surg 1985; 148:435-440). However, it was noted that the Mills/Leather knives which cut fairly well when new, became dull with use and would either slip off and miss the cusp or disrupt it with undue force and trauma. While options are available for preserving the atraumatic technique, these options all suffer from important drawbacks and deficiencies. For example, one option was to buy the knives in bulk for about $30.00 each and consider them disposable. Another option was to resharpen the knives with jewelers instruments once or twice to maintain a relatively sharp edge. However, the knives now are resharpened too often until they become a blunt hook which is traumatic and ineffective. While it has been suggested to use obsidian or some other metal which would take and hold a sharper edge longer; unfortunately, such a knife edge would be very costly. A diamond knife has been developed which is sharp and cuts very easily. However, it is expensive (about $900) and eventually becomes dull with about 120 or more valvotomies or about 25 to 30 venous grafts.
In the 1920's, Dr. Harvey Cushing and Dr. W. T. Bovie developed a dual purpose electro-surgical unit for coagulation of bleeders and for cutting tissue. When the triode vacuum tube was invented, it was possible to produce current that was pure and easy to regulate. High frequency electrical current for pure cutting or coagulation is now used in about 80% of operating room procedures as well as in office practice of dermatology, gynecology, urology, proctology, oral surgery and other specialities. It is also used during cystoscopy with the electronic cutting accomplished in a liquid medium.